Many of the great successes of particle physics involve symmetries of nature and the occasional violation of those symmetries. Discoveries such as the Higgs boson are strong vindications of this view of the world and of the Standard Model that describes these particles.

An extension to the Standard Model, called supersymmetry, takes this idea further by incorporating symmetries of space-time, as the name suggests. One side effect of supersymmetry in particle physics is the prediction of a partner to each known particle, which (among other things) could help solve the mystery of dark matter.

Despite intensive searches at the Large Hadron Collider, none of these supersymmetric partners have been detected in nature yet. However, Tarun Grover, D. N. Sheng, and Ashvin Vishwanath proposed in a new paper that an analog of supersymmetry could exist in certain exotic superconducting systems. By manipulating the characteristics of materials called "topological superconductors," researchers should be able to change particle-like excitations into their supersymmetric partners. The similarity in the physical description of these different systems could provide some important insights into the possible nature of supersymmetry and its violation in nature.

The fundamental constituents of matter—electrons, quarks, and their relatives—are known as fermions; the particles associated with fundamental forces are bosons. (The names are in honor of Italian physicist Enrico Fermi and Indian physicist Satyendra Nath Bose.) The Standard Model of particle physics explains the relationship between these particles and the symmetries that govern their behavior. In particular, the Higgs boson is the result of an imperfect symmetry inherent in the weak force.

Space-time itself also possesses certain symmetries, which are described in the theory of relativity. Additionally, Noether's theorem (discovered by German mathematician Emmy Noether) states that a symmetry implies a conservation law. Moving a physical system—a decaying atomic nucleus, for example—an arbitrary distance shouldn't affect the decay behavior. That invariance is known as translational symmetry, and Noether's theorem associates it with the conservation of momentum.

Combining the rules of particle physics and this translational symmetry (along with some other aspects of relativity) yields supersymmetry, often abbreviated as SUSY. The side effect of this symmetry: every boson should have a fermion partner and vice versa.

Except they don't. There are more fermions than bosons in the Standard Model, and we don't see these partners in ordinary experiments. So, if it exists, SUSY must be a broken symmetry of nature. The predicted consequence of this brokenness is that the SUSY particles (which have Jabberwockian names like "squark" and "bino") should be much more massive than their Standard Model counterparts. In particular, the lowest-mass SUSY particles are heavy enough to be dark matter particles.

To date, particle physics experiments have yet to turn up any sign of SUSY. However, a number of theories over the years have postulated equivalent behavior could exist in certain very cold materials. In such systems, interactions between electrons and atoms produce quasiparticles—particle-like excitations that can have masses, electric charges, and magnetic properties very different from the electrons that created them. Quasiparticles can act like free particles that move close to the speed of light, and their interactions can mimic the behavior of the Higgs field and other complex phenomena in particle physics.

Further Reading

The new paper discussed the idea of emergent SUSY-like behavior in topological superconductors. In these systems (described in more detail in the sidebar story), the interior of the material conducts electricity without resistance, but the outside is an ordinary conductor. The authors argued that experimentally observed magnetic behavior on the conducting surface could be interpreted super symmetrically. It also exhibits a breaking of SUSY due to the fundamental difference in interior and surface behavior of the system.

In this view, the magnetic excitations (acting like bosons) on the surface are SUSY partners with the topological superconductor quasiparticles, which are fermions. The behavior of this system (due to the nature of the materials) is two- or three-dimensional, whereas the SUSY of particle physics is four-dimensional. Nevertheless, the paper makes a strong argument that a direct analog to SUSY could already exist in exotic materials—an important result.

The question we must ask, of course, is whether emergent supersymmetric behavior—however intriguing—tells us anything about the nature of fundamental particles. (Physicists have a similar conundrum with the quantum simulation of a magnetic monopole.) To phrase it another way: we don't know if SUSY partners exist as fundamental particles in this Universe, regardless of whether topological superconductors behave the way physicists predict they should. These materials are interesting in their own right, however, and their study reveals a lot about the nature of collective quantum systems.

interesting article, I am particularly happy to see it brought down to layman status while still treating us like intelligent beings. I applaud this. I do have a few questions on it, for example the Higgs, what class is it in? and how does this class differ over the other particles, especially the force carrying ones?

interesting article, I am particularly happy to see it brought down to layman status while still treating us like intelligent beings. I applaud this. I do have a few questions on it, for example the Higgs, what class is it in? and how does this class differ over the other particles, especially the force carrying ones?

The Higgs is a boson, the same as the more "traditional" gauge bosons associated with the fundamental forces. In fact, from a phenomenological perspective, the higgs field can be treated in an identical way to the other forces.

Fermions and Bosons are defined by whether or not they are bound by the Exclusion Principle, not what category they fall into.

Well technically the distinction is whether they have integer or half integer spin.... That said, this seems to be a reasonable explanation for lay people. Force carrying particles have to have integer spin, to do otherwise would cause matter to switch between bosonic and fermionic any time it interacted with the force carrying particle and if matter particles were bosonic then there would be no such thing as atomic structure, so we wouldn't exist. Even though the description is a bit vague, it's still completely correct.

Your statement "Additionally, Noether's theorem (discovered by German mathematician Emmy Noether) states that a symmetry implies a conservation law" falls short of the actual statement "that any differentiable symmetry of the action of a physical system has a corresponding conservation law".

"An extension to the Standard Model, called supersymmetry, takes this idea farther by incorporating symmetries of space-time, as the name suggests"

What? How does "supersymmetry" suggest anything about space-time? "Spacetimetry" maybe, but forgive me for saying your logic is unclear here.

"Force carrying particles have to have integer spin, to do otherwise would cause matter to switch between bosonic and fermionic any time it interacted with the force carrying particle and if matter particles were bosonic then there would be no such thing as atomic structure, so we wouldn't exist"

"An extension to the Standard Model, called supersymmetry, takes this idea farther by incorporating symmetries of space-time, as the name suggests"

What? How does "supersymmetry" suggest anything about space-time? "Spacetimetry" maybe, but forgive me for saying your logic is unclear here.

"Force carrying particles have to have integer spin, to do otherwise would cause matter to switch between bosonic and fermionic any time it interacted with the force carrying particle and if matter particles were bosonic then there would be no such thing as atomic structure, so we wouldn't exist"

What? So Helium-4 doesn't exist?

Helium-4 is a composite boson, the individual particles are fermions. If, for example, electrons were bosonic then there would be no electron shell structure and modern chemistry would simply not exist.

Well technically the distinction is whether they have integer or half integer spin.... That said, this seems to be a reasonable explanation for lay people. Force carrying particles have to have integer spin, to do otherwise would cause matter to switch between bosonic and fermionic any time it interacted with the force carrying particle and if matter particles were bosonic then there would be no such thing as atomic structure, so we wouldn't exist. Even though the description is a bit vague, it's still completely correct.

Spin is derived from the exclusion principle relationship. The fundamental observation is whether they obey the exclusion principle, not whether they have half-integer spin. The value of spin is arbitrary.

By your logic it would be just as well to call them all 'basic particles' - but if you're going to describe them in detail, then do it correctly, not in a vague and hand-wavy way.

Observing supersymmetry in nature is not new. I remember a description in Peter Freund's book on supersymmetry of an experiment where absorption of a gas by a surface demonstrated supersymmetry ( Helium by tungsten I think, but check the book ).

Spin is derived from the exclusion principle relationship. The fundamental observation is whether they obey the exclusion principle, not whether they have half-integer spin. The value of spin is arbitrary.

By your logic it would be just as well to call them all 'basic particles' - but if you're going to describe them in detail, then do it correctly, not in a vague and hand-wavy way.

Whilst the scaling of spin is arbitrary the relationship between the values of bosonic and fermionic spin is not. Spin is a fundamental property of any particle obeying the dirac equation and you can find from the dirac equation that any particle obeying it will have spin-1/2 (times whatever scaling you're using) and you can then show that any particle with spin-1/2 (with scaling) will obey fermi-dirac statistics. You can show this in reverse too, they both imply each other but spin is the actual physical, measureable property of a single particle. If you have a single particle you can't measure which type of statistics it obeys.

Spin is the fundamental observable, the stern-gerlach experiment for example can precisely find the spin of a type of particle, Spin-1/2 -> Split into two beams, Spin 1 -> Split into 3 beams, Spin 3/2 -> Split into 4 beams etc.

TIL that armchair physicists are pedants. Seriously guys, it'd be nice to read the comments section and hear about all the cool implications of the physics involved instead of arguing over the simplified definitions and distinctions between what is a fermion and a boson.

For example, does this imply we can study super-conductors to learn anything about actual SUSY particles? If so, does this imply we may eventually come to a testable theory on dark matter along this line of research?

TIL that armchair physicists are pedants. Seriously guys, it'd be nice to read the comments section and hear about all the cool implications of the physics involved instead of arguing over the simplified definitions and distinctions between what is a fermion and a boson.

For example, does this imply we can study super-conductors to learn anything about actual SUSY particles? If so, does this imply we may eventually come to a testable theory on dark matter along this line of research?

As the article said, the existence of a form of supersymmetry in topological superconductors only implies that the mathematical structure of the laws describing the two systems are the same. It doesn't tell us anything directly about supersymmetric fundamental particles, but its possible it could teach us some lessons about how the math plays out in a physical system. Its not always obvious what sorts of emergent phenomena may exist. That could shed some light on fundamental physics. Its doubtful it will cause a revolution in our understanding, but you never know. We may just be lacking one key insight to unravel the puzzle of supersymmetry. It certainly seems like we are lacking SOMETHING because supersymmetry is a pretty elegant theory (or class of theories really). So far its been rather hard to come up with alternatives that make sense and haven't been ruled out already.

This is a bit off-topic, but I realized how the light-speed limit works. Triggered by a TED talk on how we exist in 11-dimentional space... I wanted to write this down somewhere before I forgot.

If space is quantized, as is asserted in the TED talk, then the speed of light and a black hole are the same phenomenon. As you travel, you encounter a new quantum within a time period. the faster your travel, the more quata you encounter in a time period. At the speed of light you are encountering quanta an a maximum rate that your motion will allow. However if your speed is low and you are encountering vast amounts of quanta, then you are in a dense region of space time. (i.e black hole) and you still have the same quanta-encounter rate limitation. The only difference is in the black hole the mass is contributory to your motion into the quanta. At the speed of light nothing is pulling you to it, so you must exert the force yourself.

Similarly, time flows fastest where matter (quanta) is least dense. This implies a time/matter correlation, expressed in E=mc^2. This is because the quanta is less dense and spread out. But the cost to move between quanta changes.

Similarly, quantum entanglement are quanta that remain connected out of the normal arrangement of matter. They are like symbolic links where their nearest quanta remains fixed to the other quanta. At lease in part.

This is a bit off-topic, but I realized how the light-speed limit works. Triggered by a TED talk on how we exist in 11-dimentional space... I wanted to write this down somewhere before I forgot.

If space is quantized, as is asserted in the TED talk, then the speed of light and a black hole are the same phenomenon. As you travel, you encounter a new quantum within a time period. the faster your travel, the more quata you encounter in a time period. At the speed of light you are encountering quanta an a maximum rate that your motion will allow. However if your speed is low and you are encountering vast amounts of quanta, then you are in a dense region of space time. (i.e black hole) and you still have the same quanta-encounter rate limitation. The only difference is in the black hole the mass is contributory to your motion into the quanta. At the speed of light nothing is pulling you to it, so you must exert the force yourself.

Similarly, time flows fastest where matter (quanta) is least dense. This implies a time/matter correlation, expressed in E=mc^2. This is because the quanta is less dense and spread out. But the cost to move between quanta changes.

Similarly, quantum entanglement are quanta that remain connected out of the normal arrangement of matter. They are like symbolic links where their nearest quanta remains fixed to the other quanta. At lease in part.

TIL that armchair physicists are pedants. Seriously guys, it'd be nice to read the comments section and hear about all the cool implications of the physics involved instead of arguing over the simplified definitions and distinctions between what is a fermion and a boson.

For example, does this imply we can study super-conductors to learn anything about actual SUSY particles? If so, does this imply we may eventually come to a testable theory on dark matter along this line of research?

To my mind, the most significant implication here is the possibility of doing more particle physics experiments at the surface physics level.

Considering what we got (and are still reaping) from the physics of doped holes of semiconductors, the potential is profound.

It is not necessary to run exotic experiments at the outset, although I hope that doesn't keep string theorists from contemplating prospects.

seems like a bunch of corner wankers to mei'd appreciate a virus that selectively targets and destroys GMOs created by monsanto (and others, i suppose) [or a nanobot that does the same]lets get some real fkn research going here, meese